Dispensing apparatus

ABSTRACT

Dispensing apparatus is provided for dispensing viscous product from containers ( 10 ) of product, usually by extruding product from a container outlet. Product is discharged by a plunger ( 13 ) which causes product to be discharged and the plunger is operated by a drive arrangement having a linear actuator ( 15 ) by which the plunger is moveable. The linear actuator uses an electric motor as the prime mover and the motor&#39;s rotary motion is converted into a linear motion of the plunger. By the use of a linear drive it is possible to achieve constant velocity of movement of the plunger independent of the resistance to movement, within the predetermined limits. The movement of the plunger can be controlled according to the resistance encountered. The apparatus also includes means for removing containers from their seating after discharge.

[0001] This invention relates to dispensing apparatus for dispensingviscous product from a container of product.

[0002] It has been proposed to dispense product, such as frozen dessert,from pre-filled containers of product by extruding the product through arelatively small opening in the container.

[0003] Hitherto the drive for discharge has usually been pneumaticallypowered and this has given rise to limitations in the dischargeespecially when the product is of varying viscosity as they do notdischarge a constant volume of product per unit time.

[0004] An object of the invention is to provide improved dispensingapparatus for extruding product.

[0005] According to one aspect of the invention dispensing apparatus fordispensing viscous product from a container of product, comprises drivemeans, a plunger operated by the drive means to move reciprocally in adispensing and a return direction, a support for the container locatableto support the container in position to be engaged by the plunger todischarge product from the container by extrusion from the container,wherein the drive means comprises a linear actuator by which the plungeris movable in a dispensing direction at a relatively constant velocity,the apparatus further comprising control means arranged to detect saidmovement and to control the operation of the drive means in accordancewith said movement.

[0006] The linear actuator is conveniently of the form comprising anelectric motor and a coupling arranged to convert rotary motion of themotor into a linear motion of the plunger, for example through a wormand worm wheel.

[0007] conveniently, the control means detects the rate of movement ofthe plunger during dispensing and provides a signal according to saidrate of movement whereby to provide an indication of the operative stateof the apparatus. In one arrangement the control means provides a signalwhich is a measurement of the movement of the plunger over unit time andcompares such movement with a predetermined rate of movement to indicatethe operative state of the apparatus, the signal being usable tointerrupt operation of the plunger.

[0008] The control means may include means for detecting the power usedby the electric motor which is a measure of the resistance to movementof the plunger.

[0009] In some cases the apparatus is arranged to detect when theresistance to the movement exceeds a predetermined amount, or amounts,and the control means interrupts the operation of the drive means, forexample when the hardness of the product is too high, or when theplunger has completed a dispensing movement and engages an abutment.Additionally or alternatively there is detected when the resistance tomovement is too low, for example when the product being dispensed is toosoft. In each case the control means may interrupt the operation, orsignal such information to the operator. Such information may be storedelectronically or by other means to assist operational efficiency,product control and after sales service. Such information may betransmitted by modem to a control centre or the information may beobtained upon request from such remote locations.

[0010] If the product is too hard, or if the plunger has completed itsdispensing movement, control means may instruct the drive to the plungerto be reversed and the plunger returned to its initial position.

[0011] The control means may also display resistance to operation and toindicate whether the resistance is too low and/or too high. Furthermeans may indicate whether a container is on the support before, or atthe end of, an operative movement of the plunger.

[0012] According to another aspect the invention provides dispensingapparatus for dispensing viscous product from a container of product,which apparatus comprises drive means, a plunger operated by the drivemeans to move reciprocally in a dispensing and a return direction, asupport for the container in a dispensing position to support thecontainer in position to be engaged by the plunger to discharge productfrom the container by extrusion, wherein the drive means is movablebetween a dispensing position in which the plunger is aligned with saidsupport and a return position in which the plunger is displaced to oneside of the support upon withdrawal away from the dispensing position.

[0013] Preferably the drive means is a linear actuator having alongitudinal axis and said axis is moved between said dispensing andreturn positions.

[0014] Preferably the drive means is pivotable about an axis, which axisis located towards the end of the drive means remote from said plunger.

[0015] Conveniently the drive means is moved between said dispensing andreturn positions by the plunger, or a part thereof, being guided along acam track extending to one side or both sides of the support.

[0016] The plunger in moving from a dispensing position is convenientlyarranged to pick up an empty container from said support and carry it toa position displaced to one side of the support for discharge from theplunger. The support may then be exposed for receiving a full containeron to the support for a dispensing operation.

[0017] Picking up of empty containers from the support may be by theplunger being a close fit in the container when discharged, by applyingvacuum between the plunger and the container, or by any other convenientmeans.

[0018] The empty container may be discharged from the plunger byengagement of the container with discharge means during withdrawal ofthe plunger towards said return position. Discharge means may be amechanical stripping guide, compressed air blast, or other means.

[0019] The container is preferably of the kind which, when ready for adispensing operation, encloses the product, except for an outletopening, and has a deformable portion which is engaged by the plunger toreduce the internal volume of the container and cause product in thecontainer to be extruded from the outlet opening. If product in suchcontainer is too soft it may be too readily dischargeable and may flowout of the container or otherwise not be dispensed correctly. If theproduct is too hard it may not be readily discharged from the container.It is also desirable that a relatively constant rate of discharge ofproduct from the container is achieved, irrespective of the producthardness. However when the plunger is moving away from a dispensingposition the drive may be at a higher speed to obtain a lower cycletime.

[0020] Different dispensing speeds can also be achieved by altering thepower supply to the motor, usually by changing the voltage.

[0021] Further features of the invention will appear from the followingdescription of embodiments of the invention given by way of example onlyand with reference to the drawings, in which:

[0022]FIG. 1A is a schematic side elevation, partly in section, of partof a dispensing apparatus according to the invention, at thecommencement of a dispensing operation,

[0023]FIG. 1B is a view corresponding to FIG. 1A at an intermediatestage during dispensing,

[0024]FIG. 1C is a view corresponding to FIGS. 1A and 1B at the end of adispensing operation;

[0025]FIG. 2 is a side elevation corresponding to FIGS. 1A, B and Cshowing the apparatus in more detail, including a support for thecontainer of product,

[0026]FIG. 3 is a view of a display for use with the apparatus,

[0027]FIG. 4 is a schematic side elevation of a second embodiment ofdispensing apparatus,

[0028]FIG. 5 is a schematic side elevation of a plunger for theapparatus of FIG. 4,

[0029]FIG. 6 is a schematic side elevation of apparatus incorporatingthe embodiment of FIG. 4

[0030]FIG. 7 is a schematic cross-section of another form of plunger forthe apparatus, in one position,

[0031]FIG. 8 corresponds to FIG. 7 showing the plunger in anotherposition,

[0032]FIG. 9 shows a side view of the plunger of FIGS. 7 and 8,

[0033]FIG. 10 shows another arrangement, in side view, of a drivearrangement, in one position,

[0034]FIG. 11 shows the arrangement of FIG. 10 in another position,

[0035]FIG. 12 is a schematic side view of another arrangement of plungerfor the apparatus of the invention,

[0036]FIG. 13 is a schematic side elevation of a further embodiment ofthe invention in an inoperative position, and

[0037]FIGS. 14, 15 and 16 are views corresponding to FIG. 13 in adispensing position, a container pick up position, and a containerdischarge position, respectively.

[0038] Referring to the drawings and firstly to FIGS. 1-3 there is showndispensing apparatus for dispensing product, for example frozen dessert,from individual containers 10 which may be of the kind shown anddescribed in PCT patent specification WO96/01224. Such containers 10 areof closed construction having a base portion 10A and a deformableportion 10B between which the product 11 is contained. In the centre ofthe base portion 10A is formed an outlet opening (not shown) throughwhich the product is to be discharged from the container 10. Thedeformable portion 10B is arranged to be deformed towards portion 10A toreduce the internal volume of the container thereby causing the product11 to be extruded from the outlet which has a cross section smaller thanthat of the container.

[0039] Deformation of the portion 10B is achieved by a plunger 12 havinga head portion 13 which, on movement of the plunger 12 in a productdischarge movement, engages the deformable portion 10B of the containerand urges it towards the base portion 10A.

[0040] The plunger 12 forms part of a drive mechanism 15 which, in thiscase, is a linear drive having an electric drive motor 16 which drives aworm and worm wheel located within a housing 17, the worm beingdrivingly connected to the plunger 12. Operation of the motor 16 isreversible so as the achieve a reciprocal movement of the plunger 12 ina dispensing direction in which the plunger 12 is extended from thehousing 17 and a return direction in which the plunger 12 is drawn backinto the housing 17. However the linear drive may take other forms eachincluding an electrically operated drive motor whose rotational movementis translated into a linear motion.

[0041] It will be appreciated that since the motor 16 is arranged torotate at a selected substantially constant speed or speeds the plunger12 also moves at a constant speed corresponding to the speed of themotor 16. However the driving force on the plunger 12 can vary, duringan operative movement, before and after a dispensing movement, andduring dispensing, according to the resistance to movement due to thehardness of product 11 within the container 10, whilst still maintaininga substantially constant rate of movement of the plunger.

[0042] It will be evident that when there is a demand for high power ofthe linear drive this is accommodated by an increase in the powerrequired of the motor 16. Since the power supplied to the motor 16 isgenerally of constant voltage the amount of amperage supplied to themotor will vary according to the power requirement.

[0043] Control means is provided for operating the linear drive 15 andthe control means detects the amperage taken by the motor 16. Inpractice a constant power supply system may be supplied to the motor 16which means that no matter what the input voltage or frequency, theconstant power supply will adjust the power output to suit therequirements of the linear actuator. A DC motor is preferred at aconstant power supply but a AC motor may also be used.

[0044] At a constant rate of movement of the plunger 12 the plunger 12moves at a fixed distance per unit time no matter what the hardness ofthe product 11 within the container, subject to a maximum predeterminedlimit on the linear actuator power. This means that a container 11holding product which is too soft for other drive systems can still bedispensed from the container 10 especially if the product has sufficientviscosity to support itself after dispensing.

[0045] However in practice the speed of the motor may vary if theresistance to movement changes significantly, for example, of the orderof about 10% of the selected speed. To counter this effect, if required,the voltage level to the motor may be increased to compensate for anincreased load and maintain the same operating speed.

[0046] The linear actuator can also handle harder product than hithertosince the power input to the linear actuator can be selected for thispurpose and this has no effect on the requirements for a softer product.Hence the range of product which can be dispensed is increased.Nevertheless product in the container 10 may be too hard for dispensing,for example because of too low a temperature, incorrect formulation ofproduct, icing up of the product in the container or a variety of otherreasons. In order to avoid damaging the apparatus and for informationpurposes the control means will enable the apparatus to avoid an attemptto dispense product which is too hard. For example if the amperagesupplied to the motor 16 is too high, i.e. above a predetermined limit,the control means may be arranged to interrupt operation of the motor.One arrangement is for the control means to be programmed to indicatetoo high an amperage reading and to interrupt operation of the drivemeans. The motor can then be arranged to reverse to its initial positionupon receipt of a signal to the control means of an excessive amperageor current being reached.

[0047] However it may be that product which is too hard at onedispensing speed can be discharged at another slower speed in which casethe dispensing speed may be reduced to dispense at that slower speedautomatically or by the operator selecting the slower speed.

[0048] Similarly the control means can be arranged to detect when theamperage of the drive motor is too low and the product is too soft. Inthis case the plunger movement may not be reversed but may continue adispensing operation but the control means indicates to the user thatthe product is too soft. If the product is detected as too soft thedispensing speed can be slowed down.

[0049] In one arrangement the control means is arranged to detect therate of movement of the plunger and whether the plunger, during adispensing operation, moves within a predetermined range of distanceover a predetermined time. If such movement is outside saidpredetermined range a signal will be generated to show a fault inoperation. This may be due to the product being too hard. The signalalerts the operator and may be used to interrupt operation of theplunger and, in some cases, to return the plunger towards it startposition. Movement of the plunger can also be halted if there is a powerdemand on the plunger exceeding a predetermined amount, for example, dueto product being too hard, the plunger movement being obstructed, theplunger reaching the container empty position, or for other reasons. Thesignal generated can activate visual or audible indicating means. Forexample a series of voice chips may be used.

[0050] In addition the control means can count the number of dispensingoperations of the apparatus together with the occasions on which theproduct is too soft or is too hard, and the number of othermalfunctions.

[0051] Referring in particular to FIG. 3 the control means may be linkedto the illustrated indicator panel on which may be indicated at 20 thenumber of dispensing operations, at 21 the viscosity of the productbeing dispensed, at 22 whether the product it too soft or too hard, at23 whether the apparatus is ready for a dispensing operation, and at 24there may be an indicator instructing the operator to remove a containerfrom the apparatus after dispensing, this being necessary for a furthercontainer to be located to dispense product.

[0052] Referring in particular to FIG. 2 the drive means and containerof FIGS. 1A, 1B and 1C are located in a housing 30 with the axis of thedrive means 15, plunger 12 and container 10 lying along an axis A whichis inclined to the vertical. The axis A can, however, be vertical. Thecontainer 10 is mounted on a support arm 31 which is hinged at 32 topivot between an operative position 31 and an inoperative position 31,in the latter position the container 10 being removable from the supportarm 31. In the operative position of the arm 31 the container is locatedin the path of movement of the plunger 12 for engagement by the plungerand a dispensing operation. The support for the container may be in theform of a seating 33 shaped according to the base 10A of the containerto support the base but leaving an opening coinciding with the outletfrom the container. The support 33 acts as an abutment to counter theaction of the plunger 12 during a discharge operation. The pivot orhinge 32 can be at any position above that shown.

[0053] Normally the product discharged from the container 10 is receivedin a cone or other container (not shown) beneath the outlet opening.

[0054] The control means may also include means for detecting thetemperature of product in the container by providing on the head 13 ofthe plunger 12, or in the container housing, a temperature probe, forexample an infrared probe, so that when the head 13 contacts thecontainer during a dispensing operation it gives a temperature reading.This may be compared with the viscosity reading obtained as previouslydescribed. By the combination of a temperature and viscosity readinginformation is available to determine the status of the apparatus and toanalyse any problems. For example re-frozen product may partially turninto solid ice which has a high viscosity and cannot be dispensed.

[0055] A product viscosity reading can be obtained at the beginning ofthe dispensing operation, possibly after a preset time of, say, fiveseconds after the dispensing operation has been commenced.

[0056] It is sometimes difficult to detect when all the product from thecontainer has been dispensed by the use of a proximity switch or otherposition detecting means. For this purpose the control means may bearranged to detect when dispensing has been completed since theresistance to the movement of the plunger 12 will be high when thecontainer is fully emptied, the support 33 acting as an abutment. Thusthe control means may be arranged to cease a dispensing operation whenthe resistance to movement of the plunger exceeds a predeterminedamount. However a position detector may be provided for this purpose.

[0057] It is also possible to use the apparatus to dispense part of thecontainer contents or to dispense containers of different sizes andproduct volume. In such an arrangement the container may be of adifferent size, preferably of the same or similar diameter but adifferent depth, in which case the plunger will move a differentdistance depending on the container size. The control means may bepre-programmed to select a movement for different containers ordifferent sizes. The operator may be able to select a different plungermovement or there may be a control arrangement operated according to theamperage detected in the drive motor. For example if a partially emptycontainer is placed in the apparatus product dispensing may be detectedand the dispensing movement adjusted accordingly. Partial discharge ofcontainers to give two or more servings is possible by programmingmovement of the plunger to give preselected movements.

[0058] Operation of the dispensing apparatus involves the followingsteps:

[0059] 1. The container 10 is placed onto the container holder 33 withthe arm 31 in position 31.

[0060] 2. The arm 31 is moved to position 31′ with the container lyingon the axis A.

[0061] 3. The arm 31 may be latched in the dispensing position by amagnet, and a motorised or solenoid lock, operated by a mechanical orother switch, may lock the arm 31 in the dispensing position. A magnetpair 35 is shown in FIG. 2.

[0062] 4. Provided that the apparatus detects that there is a container10 in position when the arm 31 is in the dispensing position 31′ thenthe dispense indicator 23 will light up to indicate that the machine isready for dispensing and the dispensing button may be pressed.

[0063] 5. Once the dispensing button is operated the linear actuatormotor 16 commences operation and the plunger 12 moves downwards anddispenses product from the container 10. Once the product has beendispensed the linear actuator retracts the plunger 12 and the arm 31 isready to be opened to position 31″or it may be arranged to openautomatically under gravity or by the use of a small linear driver.

[0064] 6. When the plunger 12 has returned fully to its uppermostposition the indicator 24 on the panel is actuated to indicate a signshowing that the empty container should be removed.

[0065] 7. As previously mentioned the panel of FIG. 3 may be fitted witha counter which will record the number of discharge operations of theapparatus. The counter may be arranged to exclude operations which havefailed due, for example, to the product being too hard. However thecounter may record all attempted dispensing operations.

[0066] 8. It is envisaged that a dispensing speed control indicator beincorporated in the control means which will enable voltage adjustmentto be provided to control the voltage to the DC motor. Alternativelythere may be provided controls which would allow different speeds ofdispensing which can be selected by the operator.

[0067] Referring now to FIGS. 4-6 there is shown another form ofdispensing apparatus, similar to the previously described embodiment,and in which the same reference numbers are used for similar parts.

[0068] A linear drive 15 is again employed having a central longitudinalaxis A and in this case the axis A is aligned with the container 10during a dispensing operation but the actuator 15 is movable about apivot axis 40 located at is end remote from the plunger 13. This isachieved by the plunger carrying transversely extending pins 41 to eachside of the plunger which are each guided for movement along a cam track42. The cam track 42 lies parallel to the axis A over its lower region42A and above the region 42A the cam track is displaced from said axis Atowards one side of the container position 10. It will be seen that thelinear actuator will, as the plunger 13 moves upwards following adispensing operation, cause the plunger 13 to move along the track 42and the linear actuator 15 has its axis A displaced from its previousdispensing position by pivoting about the axis 40 so that when theplunger 13 is at its most elevated position the linear actuator 15assumes the position shown at 15 A in FIG. 4. In this position theplunger 13 lies to one side of its dispensing position and, as can beseen from FIG. 6, it lies above a container 44 in which empty containers10 are to be discarded.

[0069] In order to achieve disposal of empty containers 10 after adispensing operation to discharge the container contents, the plunger 13picks up the container 10 from its support and carries the containeruntil the linear actuator 15 reaches position 15 A. Such picking up ofthe container may be achieved in several ways, see FIG. 5. The plunger13 may, after fully discharging the contents of the container be a closefit within the base part 10A of the container. Additionally oralternatively a vacuum may be applied between the base of the plunger 13and the container base 10A through a vacuum duct 45. As a furtheralternative the plunger 13 may be of resilient material towards itslower end whereby it can enter the container by flexing inwards whilstgripping the container at the same time.

[0070] The container is stripped from the plunger 13 as the actuatorreaches position 15 A by engagement of the container with a stripper bar(not shown) located in the path of the container as it moves from thedispensing position to the discharge position. Other means of containerremoval may be used including air blast through the plunger.

[0071] Referring now particularly to FIG. 6 there is shown the apparatusof FIG. 4 located within a housing 46 so that the upper end of thelinear actuator is supported about the pivot 40 situated towards theupper end of the housing 46. The housing 46 encloses the apparatus butis provided with an access opening 47 closable by flap 48 whereby uponraising the flap 48 access through the opening 47 may be achieved. Theflap may be kept closed by, for example an electromagnet, until theactuator is in the up position and may be automatically opened at theappropriate time.

[0072] With the flap 48 in the open position and with the plunger 13displaced to one side of the container support a new filled containermay be placed on the support prior to the plunger 13 being extended fromthe linear actuator 15. With a fresh filled container 10 in position onthe support the actuator 15 is energised to extend the plunger in adispensing direction thereby causing the plunger to move along the camtrack 42 until it is above the filled container and further movementalong the axis A causes the plunger to engage the container anddischarge the contents through the opening at the lower part of thecontainer support. The operator locates a receiving vessel or cone belowthe container outlet to receive the product from the container.

[0073] Below the support is located a drip tray 49 for catching anyproduct which does not enter the receiving vessel.

[0074] Below the housing 46 is a base unit 50 on which the housing 46 issupported and the base unit contains, removably, the bin 44 for emptycontainers. An empty container chute may be fitted for guiding thereleased empty containers from the plunger into the discharge bin. Thischute is removable for cleaning if required. The chute can also bedesigned to direct empty containers out the side or back of thedispenser for countertop applications. A further alternative is to fit anesting tube below the discharge point of the empty containers fornesting together such containers for minimum space requirements of thecontainers.

[0075] At two positions spaced apart along the axis A the linearactuator 15 carries proximity switches 51 and 52, the switch 51determining the uppermost position of the linear actuator and theposition 52 determining the lowermost position.

[0076] There has previously been described an arrangement by which theforce required to drive the plunger has been detected electrically so asto prevent the drive from trying to discharge product which is too hardand/or to determine when the plunger has fully discharged the container.Instead of electrical overload protection means, as described, amechanical arrangement can be employed such as shown in FIGS. 7-11.

[0077] In the arrangement of FIGS. 1-4 the plunger 13 is formed as anassembly including a plunger component 13A and a relatively movableplunger component 13B between which is located a compression spring 55.As seen in FIG. 9 the component 13B is attached to the component 13Athrough pins 56 mounted on the component 13A and extending outwardlythrough slots 57 formed in the component 13B whereby the component 13Bcan be moved relative to the component 13A against the action of thespring 55. The spring 55 would normally be in an extended condition, asshown in FIG. 7, but when the force on the plunger exceeds apredetermined value then the spring 55 is compressed to the positionshown in FIG. 8. In this case the component 13 B, which is the partengaging with the container, fails to reach a discharge position anddischarge of the container is not achieved. This will occur when theresistance to movement of the plunger exceeds a predetermined value. Theposition of the component 13B can be detected by a position probe 58which detects that the component has not moved to a container dischargeposition, and signals to the operator.

[0078] Referring now to FIGS. 10 and 11 an alternative mechanicalpressure detector is shown. In this arrangement the upper end of thelinear actuator 15 is carried, pivotally, on an assembly 60 which islocated with a fixed plate 61 mounted on the housing and atelescopically movable member 62, movable in relation to the fixed plate61. Located between the movable and fixed members 62, 61 there isprovided a spring 63 which compresses under a predetermined axial loadarranged to be such that it detects when the product within thecontainer 10 is too hard. Under such circumstances the spring 63 iscompressed, as shown in FIG. 11, and the product cannot be dispensedfrom the container.

[0079] All of the mechanical devices described above can include limitswitches or other detection devices to indicate too hard or too softsituations. This information can be transmitted to the control of thedispenser to carry out similar functions to those already describedabove.

[0080] Referring now to FIG. 12 there is shown an arrangement by which afailure to remove an empty container from the support is detected. Ashroud 65 is arranged around the plunger 13 as it passes from a returnposition towards a dispensing position. The shroud 65 is sized so thatas the shroud 65 is lowered towards the container support it will engagea duplicate container if it has been placed on top of an emptycontainer. In its normal mode the shroud 65 will contact a container onthe support in a lower position. Thus in this mode the lower end of theshroud 65 is arranged so that at its lower end it is located within ashort distance of the upper end of the container. Limit switches 66detect the position of the upper end of the shroud and if these limitswitches are actuated prior to the limit switches detecting movement ofthe linear actuator 15 then the system will generate a signal indicatingthat there is a new container which has been loaded inside an emptycontainer which has not been removed. The location of the lower end ofthe plunger 13 in relation to the lower end of the shroud is arranged toavoid any possibility that the operator has fingers in the wrongposition. It will also be appreciated that the presence of anobstruction will be detected due to the drive force on the linearactuator being greater than should be the case. The shroud 65 alsoserves the function of compressing the lid of the container 10 onto thebase 10A by engaging the edges of the lid where they are located ontothe base.

[0081] An amperage detecting circuit can be installed to ensure that if,before dispensing is intended to commence, the drive amperage exceeds apreset maximum, then the linear actuator will be instructed either tostop or return upwards to its starting position.

[0082] FIGS. 13-16 show an alternative arrangement by which containersare removed from the apparatus after discharge of contents fromcontainers.

[0083] In this arrangement the apparatus is similar to that of FIGS.1A-1C and the same reference numbers are used for similar parts. In thiscase, however, as well as the linear drive 15 for dispensing productsfrom the containers 10, there is provided a further linear or otherdrive 70 which is for picking up and removing the containers from theirseating, after discharge. The drive 15 is mounted with its housing fixedto the housing 30 of the apparatus so that the plunger 13 movesreciprocally of the central axis of the drive 15 to make a discharge andreturn movement. In FIG. 13 the plunger 13 is in its retracted positionprior to a discharge movement.

[0084] In FIG. 14 the plunger 13 has moved to a discharge position inwhich the container contents are extruded from the container 10, in themanner described previously.

[0085] The plunger 13 returns towards its initial position and the drive70 operates its associated pick up plunger 73 which moves to pick up anddischarge the empty containers. The axis of the drive 70 and plunger 73is inclined to the vertical and inclined to the axis of drive 15, and issupported for pivotal movement about a pivot 74 to change theorientation of the axis of the drive 70.

[0086] The plunger 73 has lateral extensions 75 which are located in andguided by cam tracks 77 located to each side of the plunger 73 so thatas the plunger is extended it passes along the track or guide defined bythe cam tracks 72.

[0087] Towards the end of the plunger movement (FIG. 15) the plunger 73reaches the empty container 10 and the plunger enters the container tobecome attached thereto by frictional engagement, by vacuum (asdescribed), or by other means. Upon retraction of the plunger 73 thecontainer 10 moves with the plunger away from its seating and to oneside of the path of the discharge plunger 13. The container carried bythe plunger 73 is then dislodged from such plunger by release of vacuum,by engagement with a fixed stripping member (not shown), or otherwise,so that the container is released from and falls under gravity from theplunger 73 into a receptacle.

[0088] In other respects the apparatus of FIGS. 13-16 operates asdescribed previously and the linear drive 15 operates in the mannerdescribed. The drive 70, in providing a simpler function than the drive15 may be constructed to move the plunger 73 reciprocally at a constantspeed in each direction, the speed being sufficient to effect speedyremoval of the containers after discharge.

[0089] It will be appreciated that the plunger speed can be changed sothat the plunger 13 travels in its reciprocating motion at faster speedswhen it is not discharging product from the container, the speed slowingdown when the driving force needs to be increased during discharge. Thuson a discharge movement the plunger may descend from its return positionto a position at which product discharge is to commence, at a fasterspeed. The plunger speed is then slowed during discharge. Uponcompleting product discharge the plunger may move to its return positionat a faster speed. This gives rise to improvements in cycle time and canbe readily achieved by detecting the position of the linear actuator andaltering the speed ratios over the relevant portions of the travel.

[0090] A portable battery pack may be installed externally or internallyto the dispenser to supply a DC supply for remote operation.

1. Dispensing apparatus for dispensing viscous product from a containerof product, comprising drive means, a plunger operated by the drivemeans to move reciprocally in a dispensing and a return direction, asupport for the container locatable to support the container in positionto be engaged by the plunger to discharge product from the container byextrusion from the container, wherein the drive means comprises a linearactuator by which the plunger is moveable in a dispensing direction at avelocity which remains substantially constant, the apparatus furthercomprising control means arranged to detect said movement and to controlthe operation of the drive means in accordance with said movement. 2.Dispensing apparatus according to claim 1 wherein the linear actuator isin the form comprising an electric motor and a coupling arranged toconvert rotary motion of the motor into a linear motion of the plunger.3. Dispensing apparatus according to claim 2 wherein the control meansincludes detection means for detecting the power used by the electricmotor as a measure of the resistance to movement of the plunger. 4.Dispensing apparatus according to claim 1, 2 or 3, wherein the controlmeans detects the rate of movement of the plunger during dispensing andprovides a signal according to said rate of movement whereby to providean indication of the operative state of the apparatus.
 5. Dispensingapparatus according to claim 4 wherein the control means provides asignal which is a measurement of the movement of the plunger over unittime and compares such movement with a predetermined rate of movement toindicate the operative state of the apparatus, the signal being usableto interrupt operation of the plunger.
 6. Dispensing apparatus accordingto any one of the preceding claims wherein the apparatus is arranged todetect when the resistance to movement of the plunger exceeds apredetermined amount, or amounts, and the control means interrupts orchanges the operation of the drive means accordingly.
 7. Dispensingapparatus according to any one of the preceding claims wherein detectionmeans detects when the resistance to movement of the plunger is too lowand provides a signal which may be used to interrupt or change theoperation of the plunger or provide an indication to the operator. 8.Dispensing apparatus according to any one of the preceding claimswherein the drive means provides signals of each operation of theplunger which signals are collected and stored by the apparatus, orremotely.
 9. Dispensing apparatus according to any one of the precedingclaims wherein the control means upon detecting that the resistance tomovement of the plunger exceeds a certain level causes the movement ofthe plunger to be reversed towards its initial position.
 10. Dispensingapparatus according to any one of the preceding claims wherein theposition of the plunger is detected and, if the plunger does not reach apredetermined position at which dispensing of product should commence, asignal is generated to indicate a malfunction, such as the presence ofan empty container in addition to a container to be dispensed, andplunger movement is interrupted.
 11. Dispensing apparatus for dispensingviscous product from a container of product, which apparatus comprisesdrive means, a plunger operated by the drive means to move reciprocallyin a dispensing and a return direction, a support for the container in adispensing position to support the container in position to be engagedby the plunger to discharge product from the container by extrusion,wherein the drive means is moveable between a dispensing position inwhich the plunger is aligned with said support and a return position inwhich the plunger is displaced to one side of the support uponwithdrawal away from the dispensing position.
 12. Dispensing apparatusaccording to claim 11 wherein the drive means is a linear actuatorhaving a longitudinal axis and said axis is moved between saiddispensing and return positions.
 13. Dispensing apparatus according toclaims 11 or 12 wherein the drive means is pivotable about an axis whichaxis is located towards the end of the drive means remote from saidplunger.
 14. Dispensing apparatus according to any one of claims 1-13wherein the drive means is moved between said dispensing and returnpositions by the plunger, or a part thereof being guided along a camtrack extending to one side or both sides of the support.
 15. Dispensingapparatus according to any one of claims 11-14 wherein the plunger isarranged to pick up an empty container from said support and carry it toa position displaced to one side of the support for discharge from theplunger.
 16. Dispensing apparatus for dispensing viscous product from acontainer of product, which apparatus comprises drive means, a plungeroperated by the drive means to move reciprocally in a dispensing and areturn direction, a support for the container in a dispensing positionto support the container in position to be engaged by the plunger todischarge product from the container by extrusion, the apparatus furthercomprising a reciprocal member moveable between a container pick upposition and a discharge position after the plunger has effecteddischarge of product from the container, the discharge position beingdisplaced to one side of the support.
 17. Dispensing apparatus accordingto claim 16 comprising a reciprocal driving arrangement operating thepick up and release member whose movement is guided during reciprocationalong a non-rectilinear path.
 18. Dispensing apparatus according toclaims 16 or 17 wherein the pick up and release member is in the form ofa reciprocal plunger.
 19. Dispensing apparatus according to any one ofclaims 11-14 and 18 wherein the plunger is a close fit into containerspermitting the containers to be picked up on the plunger, release of thecontainers from the plunger being by engagement with a release member,by the application of air discharged from the plunger, or the like. 20.Dispensing apparatus according to any one of the preceding claimswherein the container is arranged to enclose product and has an outletopening, a deformable portion of which is engaged by the plunger toreduce the internal volume of the container and cause product in thecontainer to be extruded from the opening.